. . . "The controller 111 drives a light source, such as a laser diode or light-emitting diode (LED), provided in the optical writing device 2 to direct laser beams (writing light) L to drum-shaped photoreceptors 4K, 4Y, 4M, and 4C. With the laser beams L, electrostatic latent images are formed on the respective photoreceptors 4K, 4Y, 4M, and 4C, which are developed into toner images in a development pro" . .